Web source for subq fluids

Hi -

My senior cat was just diagnosed with CRF, and we need to give him subq fluids. I found a website called entirelypets.com that sells lactated ringers much cheaper than my vet, but my vet was concerned that the supplies may not be of good quality so they didn't want to issue a prescription directly to them. So, has anyone had experience with ordering supplies from this website, and if not does anyone know of a good source for subq supplies?

Thanks!

I buy my dogs' heartworm prevention from entirelypets.com (prescription only - my vet faxes a prescription to them). I also get my flea control from them, and my experiences have all been positive so far. I have no idea about the fluids, though.